Improvement in vault-lights



l. M. WILLBUR.

Vault-Lights.

Patened Apr|21,1874.

UNITED STATES PATENT OFFICE.,

JAMES M. WILLBUR, OF NEW YORK, N. Y.

IMPROVEMENT IN VAULT-LIGHTS.

Specification forming part of letters Patent No. 150,118, dated April21, 1874; application iled January 28,1874.

CASE C.

To all whom it may concern:

Beit known that I, J AMES M. WILLBUE, of the city, county, and State ofN ew York, have invented certain new and useful Improvements inVault-Lights; and I do hereby declare the following to be a full andexact description of thesame, reference being had to the accompanyingdrawings forming part of this specication, in which- Figure l is aperspective view of my improved vault-light. Fig. 2 is a sectional viewin the line z z, Fig. l. Fig. 3 is a perspective view of the lower plateof Fig. 2; and Fig. 4 is a sectional view through the line y y, Fig. 3.

Similar letters of reference in the accompanyin g drawings denote thesame parts.

My invention consists in the employment in vault-lights of two plates,similarly formed, connected together by bolts or other fastenings, eachplate being provided with tapering perforations fitting over each otherfor the reception of barrel-shaped lights, the whole being reversible,so that when the upper surface of the vault-cover or sidewalk has beenworn away it may be turned over and afford a new nearing-surface.

In the accompanying drawings, o p are two plates, joined together bybolts and nuts, or other similar fastenings, and provided. with taperingperforations q q, so that when the two plates are fastened together, thelarger diameters of the perforations q q in the plates will lie directlyover each other, and the perforations between the plates will present abarrel-shaped form; or, more strictly speaking,

the perforations in the two plates, when one is placed over the other,are of the form of two frustums of 'a cone with their larger bases incontact. Vaultlights a a, of the form of two frustums of a cone unitedat their bases, are inserted in each of the perforations q q in theplates o p before they are fastened together.

In lieu of barrel-shaped lenses in some cases I design to employtruncated pyramidal-shaped lenses, the bases of the truncated pyramidsbeing in contact and united together; or, in lieu of the latter, lenseshaving any number of sides, with their bases in contact, and made in onepiece, may be employed, the object of this part of my invention being tomake the lens of greater circumference at its middle than elsewhere inorder to retain it in place between the plates.

It will be seen from this construction that the plates o p can readilybereversed, or turned

